In an existing display apparatus, an organic electroluminescent display (OLED, Organic Light Emitting Diode) has advantages of simple manufacturing process, low cost, high luminous efficiency and being easy to form a flexible structure etc.; a liquid crystal display (LCD) has advantages of low power consumption, good displaying quality, no electromagnetic radiation and wide application area etc. Currently, both the organic electroluminescent display and the liquid crystal display are the important display apparatuses.
Voltages are applied to a pixel electrode and a common electrode in the liquid crystal display respectively, a electric field formed between the pixel electrode and the common electrode controls liquid crystal molecules to rotate and the liquid crystal molecules modulate backlights transmitted, so that the backlight is enabled to irradiate to a color film layer, which has different light intensity transmittances for different spectral bands, in different light intensities, and finally the light of the required color is presented. The voltages are applied to an anode (i.e., the pixel electrode) and a cathode (i.e., the common electrode) in the organic electroluminescent display respectively, cavities generated at the anode and electrons generated at the cathode compose excitons at a light-emitting layer, energies of the excitons are transferred to light-emitting molecules in the light-emitting layer, so that the electrons in the light-emitting molecules emit light due to a radiative recombination.
In the existing liquid crystal displays and organic electroluminescent displays, the common voltage applied to a common electrode line by a common voltage generation circuit may increase or decrease because such a common voltage is likely to be affected by other voltages, which would result problems such as shaking, stick images, gray scale abnormity in the displaying and crosstalk etc. in a picture displayed by the liquid crystal display and the organic electroluminescent display, thus displaying qualities of the liquid crystal display and the organic electroluminescent display are affected.
Accordingly, the common voltage on the common electrode line is needed to be stabilized.